U.S. patent number 7,873,000 [Application Number 10/591,712] was granted by the patent office on 2011-01-18 for random access method and radio communication terminal device.
This patent grant is currently assigned to Panasonic Corporation. Invention is credited to Jun Cheng, Kenichi Miyoshi, Akihiko Nishio.
United States Patent |
7,873,000 |
Cheng , et al. |
January 18, 2011 |
Random access method and radio communication terminal device
Abstract
There are disclosed a random access method for establishing an
individual channel between a radio communication terminal device
and a base station device in a short time and a radio communication
terminal device executing the random access method. In this device,
in step ST320, a RACH sub-channel allocation unit (211) allocates a
transmission packet inputted from a replication unit (202) to an
arbitrary sub-carrier at the RACH arbitrary time slot at random. In
step ST330, an allocation unit (210) judges whether an overlap is
generated in the allocation result obtained by the RACH sub-channel
allocation unit (211). When the allocation unit (210) judges that
an overlap is generated in the allocation result, the allocation
unit (210) causes one of the RACH sub-channel allocation units
(211) which has caused the overlap to again perform allocation of
step ST320. On the other hand, when judgment is made that no
overlap is generated in the allocation result, step ST340 is
executed.
Inventors: |
Cheng; Jun (Kyoto,
JP), Nishio; Akihiko (Kanagawa, JP),
Miyoshi; Kenichi (Kanagawa, JP) |
Assignee: |
Panasonic Corporation (Osaka,
JP)
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Family
ID: |
34918262 |
Appl.
No.: |
10/591,712 |
Filed: |
February 28, 2005 |
PCT
Filed: |
February 28, 2005 |
PCT No.: |
PCT/JP2005/003329 |
371(c)(1),(2),(4) Date: |
September 06, 2006 |
PCT
Pub. No.: |
WO2005/086520 |
PCT
Pub. Date: |
September 15, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070195730 A1 |
Aug 23, 2007 |
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Foreign Application Priority Data
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Mar 9, 2004 [JP] |
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2004-065625 |
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Current U.S.
Class: |
370/329; 455/434;
370/468; 455/517; 370/347; 455/515; 370/229; 455/516; 370/469 |
Current CPC
Class: |
H04W
74/0833 (20130101); H04W 72/087 (20130101); H04W
72/04 (20130101); H04W 72/10 (20130101); H04W
72/0446 (20130101); H04W 72/0413 (20130101); H04W
74/004 (20130101); H04W 36/16 (20130101); H04W
88/08 (20130101) |
Current International
Class: |
H04W
4/00 (20090101) |
Field of
Search: |
;370/229,329,469,347,350,468,341,340,335,345
;455/434,515,516,517,466 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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9214507 |
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Aug 1997 |
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JP |
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200144969 |
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Feb 2001 |
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JP |
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2001268051 |
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Sep 2001 |
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JP |
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Other References
PCT International Search Report dated Jun. 14, 2005. cited by other
.
Keiji Tachikawa, "W-CDMA Mobile Communication Scheme," Maruzen Co.,
Ltd., pp. 45-47, Jun. 25, 2001, with partial English translation.
cited by other.
|
Primary Examiner: Sheikh; Ayaz R
Assistant Examiner: Lee; Andrew C
Attorney, Agent or Firm: Dickinson Wright PLLC
Claims
The invention claimed is:
1. A transmitting method comprising: receiving information which is
transmitted from a base station apparatus, wherein said information
specifies a number; generating, based on said number, a
transmission signal comprised of access signals which are
consecutive in a time domain and which include an access signal and
at least one duplication of said access signal, wherein said access
signals are identical in number to said number specified by said
information; and transmitting said transmission signal, from a
terminal apparatus, on at least two consecutive time slots using a
resource selected at random from resource candidates.
2. The transmitting method according to claim 1, wherein the
resource candidates are a timing, a transmission frequency, or a
spreading code.
3. A terminal apparatus comprising: a receiving section configured
to receive information which is transmitted from a base station
apparatus, wherein said information specifies a number; a
generating section configured to generate, based on said number, a
transmission signal comprised of access signals which are
consecutive in a time domain and which include an access signal and
at least one duplication of said access signal, wherein said access
signals are identical in number to said number specified by said
information; and a transmitting section configured to transmit said
transmission signal on at least two consecutive time slots using a
resource selected at random from resource candidates.
4. The terminal apparatus according to claim 3, wherein the
resource candidates are a timing, a transmission frequency, or a
spreading code.
Description
TECHNICAL FIELD
The present invention relates to a random access method in a radio
communication system composed of a plurality of radio communication
terminal apparatuses and base station apparatuses, and a radio
communication terminal apparatus of the random access method.
BACKGROUND ART
Conventionally, in a radio communication system by a cellular
scheme, when a radio communication terminal apparatus starts or
restarts communication, an individual channel between the radio
communication terminal apparatus and the base station apparatus is
not established yet, and the radio communication terminal apparatus
is therefore designed to attempt an access to the base station
apparatus using a random access channel (hereinafter "RACH": Random
Access Channel). For example, in the radio communication system by
a W-CDMA scheme, a slotted ALOHA scheme is adopted. When each of a
plurality of radio communication terminal apparatuses start or
restart communication, access to the base station apparatus is
attempted at an arbitrary timing out of start timing candidates
(RACH subchannel). If there is no response from the base station
apparatus within predetermined time from the access time, the
access is determined failed, and access to the base station
apparatus is attempted again (see, for example, Non-Patent Document
1).
Further, in the radio communication system by a multi-carrier
transmission scheme, a technology is known in which when
transmission packet is transmitted to the base station apparatus by
RACH for establishing an individual channel, the radio
communication terminal apparatus selects slot (timing) and
subcarrier (frequency) of RACH and spreading code based on certain
conditions, spreads the transmission packet by the selected
spreading code, and then transmits the packet to the base station
apparatus at the selected timing and frequency (see, for example,
Patent Document 1). Furthermore, in a technology disclosed in
Patent Document 1, a radio communication terminal apparatus
attempts an access to the base station apparatus, and if there is
no response from the base station apparatus within predetermined
time from the access time, the radio communication terminal
apparatus attempts an access to the base station apparatus again.
Patent Document 1: Japanese Patent Application Laid-Open No.
2001-268051 Non-Patent Document 1: Keiji Tachikawa (ed.), "W-CDMA
Mobile Communication Scheme," Maruzen Co., Ltd., p. 45, Jun. 25,
2001
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
However, in technologies disclosed in Patent Document 1 and
Non-Patent Document 1, a plurality of radio communication terminal
apparatuses attempt an access to the base station apparatus by RACH
and access to the base station apparatus is attempted again after
determining success or failure for establishing individual channels
so that a case may occur when establishing the individual channel
after the first access to the base station apparatus may require
time. Furthermore, the number of transmission packets transmitted
by RACH increases as the number of radio communication terminal
apparatuses belonging to the same cell increases so that the
likelihood of collision of transmission packets becomes high and
establishing the individual channels requires longer time. For this
reason, with the conventional technology, the problems of
deterioration of communication quality and non-accessible state for
communication and the like are made more likely to occur in the
radio communication terminal apparatus designed to plan a service
demanding a QoS (Quality of Service) delay requirement.
It is therefore an object of the present invention provide a random
access method for establishing an individual channel between a
radio communication terminal apparatus and a base station apparatus
in a short time, and a radio communication terminal apparatus for
operating this random access method.
Means for Solving the Problem
A Random access method according to the present invention includes
a duplication step of duplicating a transmission packet, an
assignment step of assigning each of a plurality of duplicated
transmission packets to a random access channel, and a transmission
step of transmitting the plurality of the transmission packets in
accordance with an assignment result in the assignment step.
According to this method, the radio communication terminal
apparatus assigns and transmits a plurality of transmission packets
to the base station apparatus by RACH so that, even when many radio
communication terminal apparatuses belong to the same cell, the
likelihood becomes high that, one of the plurality of transmission
packets is received by the base station apparatus without colliding
with transmission packets transmitted from other radio
communication terminal apparatuses. As a result, according to this
method, the radio communication terminal apparatus transmits the
duplicated transmission packets to RACH without waiting for a
response from the base station apparatus to confirm whether or not
the transmission packets transmitted to RACH are received at the
base station apparatus, thereby establishing an individual channel
to the base station apparatus in a short time.
The random access method according to the present invention
includes, in the above-mentioned invention, a determination step of
determining the number of duplications of the transmission packet
in the duplication step according to a priority of service planned
after communication is started.
According to this method, in addition to the effect of the
invention, the number of transmission packets transmitted to RACH
by the radio communication terminal apparatus is determined
according to kinds of services planned after the individual channel
is established so that, out of the plurality of the radio
communication terminal apparatuses belonging to the same cell, one
with higher urgency is more likely to establish the individual
channel. As a result, according to this method, the problems of
deterioration of communication quality, non-accessible state for
communication and the like are made less likely to occur in the
plurality of the whole radio communication terminal apparatuses
belonging to the same cell.
The random access method according to the present invention
includes, in the above-mentioned invention, a determination step of
determining the number of duplications of the transmission packet
in the duplication step according to the number of retransmissions
of the transmission packet.
According to this method, in addition to the effect of the
invention, the number of duplications of the transmission packet
increases according to the number of retransmissions of
transmission packets so that, out of the plurality of the radio
communication terminal apparatuses belonging to the same cell, one
with higher urgency is more likely to establish the individual
channel. As a result, according to this method, the problems of
deterioration of communication quality, non-accessible state for
communication and the like are made less likely to occur in the
plurality of the whole radio communication terminal apparatuses
belonging to the same cell.
The random access method according to the present invention
includes, in the above-mentioned invention, a determination step of
determining the number of duplications of the transmission packet
in the duplication step according to the number of the radio
communication terminal apparatuses belonging to the same cell and
using said random access channel.
According to this method, in addition to the effect of the
invention, if the number of the radio communication terminal
apparatuses belonging to the same cell increases, radio
communication terminal apparatuses make less the number of the
duplications of the transmission packet so that it is possible to
reduce the likelihood of collision of transmission packets. As a
result, according to this method, the problems of deterioration of
communication quality, non-accessible state for communication and
the like are made less likely to occur in the plurality of the
whole radio communication terminal apparatuses belonging to the
same cell.
With the random access method according to the present invention,
in the assignment step of the above-mentioned invention, each of
the plurality of duplicated transmission packets are assigned to
one of time slots in the random access channel.
With the random access method according to the present invention,
in the assignment step of the above-mentioned invention, each of
the plurality of duplicated transmission packets are assigned to
one of subcarriers in the random access channel.
According to these methods, in addition to the effect of the
invention, the radio communication terminal apparatus assigns the
plurality of transmission packets randomly to one of time slots and
subcarriers of RACH so that it is possible to reduce load of the
signal processing necessary for the assignment of transmission
packets in the radio communication terminal apparatus.
With the random access method according to the present invention,
in the assignment step of the above-mentioned invention, each of
the plurality of duplicated transmission packets are assigned to
one of time slots and one of subcarriers in the random access
channel.
According to this method, in addition to the effect of the
invention, the radio communication terminal apparatus assigns the
plurality of transmission packets randomly to time slots and
subcarriers of RACH so that, even when many radio communication
terminal apparatuses belong to the same cell, it is possible to
reduce the likelihood of collision of the transmission packets.
With the random access method according to the present invention,
in the assignment step of the above-mentioned invention, each of
the plurality of duplicated transmission packets are assigned to
one of spreading codes in the random access channel.
According to this method, in addition to the effect of the
invention, the plurality of radio communication terminal
apparatuses spread and transmit the transmission packets to the
base station apparatus using the spreading codes selected randomly
so that, even when many radio communication terminal apparatuses
belong to the same cell, it is possible to reduce the likelihood of
collision of transmission packets.
A radio communication terminal apparatus according to the present
invention adopts a configuration having: a duplication section that
duplicates a transmission packet; an assignment section that
assigns each of the plurality of duplicated transmission packets to
a random access channel; and a transmission section that transmits
the plurality of transmission packets in accordance with an
assignment result in the assignment section.
According to this configuration, the radio communication terminal
apparatus assigns the plurality of the duplicated transmission
packets randomly to RACH and transmits the transmission packets to
the base station apparatus so that, even when many radio
communication terminal apparatuses belong to the same cell, the
likelihood becomes high that, the plurality of transmission packets
are received by the base station apparatus without colliding with
transmission packets transmitted from other radio communication
terminal apparatuses. As a result, according to this configuration,
the radio communication terminal apparatus transmits the duplicated
transmission packets to RACH without waiting for a response from
the base station to confirm whether or not the transmission packets
transmitted to RACH are received at the base station, thereby
establishing an individual channel to the base station apparatus in
a short time.
Advantageous Effect of the Invention
According to the present invention, the plurality of the radio
communication terminal apparatuses assign the plurality of the
duplicated transmission packets randomly to RACH and transmits the
transmission packets to the base station apparatus so that, even
when many radio communication terminal apparatuses belong to the
same cell, the likelihood becomes high that, the plurality of
transmission packets are received by the base station apparatus
without colliding with transmission packets transmitted from other
radio communication terminal apparatuses. As a result, according to
this invention, the radio communication terminal apparatus
transmits the duplicated transmission packets to RACH without
waiting for a response from the base station apparatus to confirm
whether or not the transmission packets transmitted to RACH are
received at the base station, thereby establishing an individual
channel to the base station in a short time.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows a configuration of a radio communication terminal
system using a random access method according to Embodiment 1 of
the present invention;
FIG. 2 is a block diagram showing a configuration of a radio
communication terminal apparatus according to Embodiment 1 of the
present invention;
FIG. 3 is a flow chart explaining a random access method according
to Embodiment 1 of the present invention;
FIG. 4A shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 4B shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 4C shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 4D shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 5A shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 5B shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 5C shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 5D shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 5E shows an assignment of a transmission packet to RACH
according to Embodiment 1;
FIG. 6 is a block diagram showing a configuration of a radio
communication terminal apparatus according to Embodiment 2 of the
present invention;
FIG. 7 is a flow chart explaining a random access method according
to Embodiment 2 of the present invention;
FIG. 8 is a block diagram showing a configuration of a radio
communication terminal apparatus according to Embodiment 3 of the
present invention;
FIG. 9 is a flow chart explaining a random access method according
to Embodiment 3 of the present invention;
FIG. 10 is a block diagram showing a configuration of a radio
communication terminal apparatus according to Embodiment 4 of the
present invention;
FIG. 11 is a flow chart explaining a random access method according
to Embodiment 4 of the present invention;
FIG. 12A shows a correlation between a priority, the number of the
radio communication terminal apparatuses belonging to the same
cell, and the number of duplications of a transmission packet
according to Embodiment 4; and
FIG. 12B shows a correlation between a priority, the number of the
radio communication terminal apparatuses belonging to the same
cell, and the number of duplications of a transmission packet
according to Embodiment 4.
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
FIG. 1 shows a schematic configuration of a radio communication
system composed of four radio communication terminal apparatuses
200-1 to 200-4 and base station apparatus 100 that establish
individual channels using a random access method according to
Embodiment 1 of the present invention. In FIG. 1, a communication
area of this radio communication system is indicated as "cell A."
Furthermore, an OFDM (Orthogonal Frequency Division Multiplexing)
signal is subjected to packet exchange in cell A of FIG. 1. In
addition, the configurations and operations of the radio
communication terminal apparatuses 200-1 to 200-4 will be explained
below, but the radio communication terminal apparatuses 200-1 to
200-4 refer to the same configuration and the same function so that
the branch numbers may be omitted when explanations of the function
and the like are made entirely.
FIG. 2 is a block diagram showing a configuration of radio
communication terminal apparatus 200. Radio communication terminal
apparatus 200 includes transmission packet generating section 201,
duplication section 202, assignment section 210, packet
multiplexing section 221, radio transmission section 222 and
antenna element 223. Furthermore, assignment section 210 includes
RACH subchannel assigning sections 211-1 to 211-c. In addition, "c"
is an arbitrary natural number of two or greater.
Transmission packet generating section 201 generates transmission
packet including information of radio communication terminal
apparatus 200 necessary for establishing an individual channel to
base station apparatus 100 when radio communication terminal
apparatus 200 is started or recovered from the idol state, and
inputs the generated transmission packet to duplication section
202.
Duplication section 202 duplicates the transmission packet input
from transmission packet generating section 201, and inputs c
duplicated transmission packets to RACH subchannel assigning
sections 211-1 to 211-c, respectively.
RACH subchannel assigning section 211 assigns the transmission
packets input from duplication section 202 randomly to arbitrary
subcarriers with arbitrary RACH time slots. Assignment section 210
compares the assignment results of RACH subchannel assigning
sections 211-1 to 211-c each other, and when transmission packets
are assigned to the same subcarrier with the same time slot with
overlap, assignment section 210 instructs one of RACH subchannel
assigning sections 211 to perform assignment again. Assignment
section 210 then instructs RACH subchannel assigning sections 211-1
to 211-c to input transmission packets to packet multiplexing
section 221 with the subcarriers of assigned time slots after
confirming that time slots and subcarriers assigned by RACH
subchannel assigning sections 211-1 to 211-c are not overlapped.
RACH subchannel assigning sections 211-1 to 211-c input
transmission packets at predetermined timing and frequency to
packet multiplexing section 221 in accordance with instructions
from assignment section 210.
Packet multiplexing section 221 multiplexes transmission packets
input from RACH subchannel assigning sections 211-1 to 211-c and
inputs multiplexed transmission packets to radio transmission
section 222.
Radio transmission section 222 is composed of S/P converter, IFFT
apparatus, P/S converter, guard interval insertion apparatus,
bandpass filter, D/A converter, low noise amplifier or the like,
and after generating an OFDM (Orthogonal Frequency Division
Multiplexing) signal from the transmission packet input from packet
multiplexing section 221, radio transmission section 222 transmits
the generated OFDM signal by radio to base station apparatus 100
through antenna element 223.
Next, the operations of radio communication terminal apparatus 200
will be explained using FIG. 3. FIG. 3 is a flow chart showing
steps of a random access method according to this embodiment.
First, in step ST310, duplication section 202 duplicates c
transmission packets input from transmission packet generating
section 201.
Next, in step ST320, RACH subchannel assigning sections 211-1 to
211-c assign the transmission packets input from duplication
section 202 randomly to arbitrary subcarriers at arbitrary time
slots of RACH.
Next, in step ST330, assignment section 210 determines whether or
not assignment results by RACH subchannel assigning sections 211-1
to 211-c are overlapped. When assignment section 210 determines
assignment results by RACH subchannel assigning section 211 are
overlapped in step ST330, assignment section 210 makes one of RACH
subchannel assigning sections 211 which has caused the overlap
perform the assignment of step ST320 again. On the other hand, in
step ST330, when assignment section 210 determines assignment
results by RACH subchannel assigning section 211 are not
overlapped, step ST340 is executed.
Next, in step ST340, radio transmission section 222 generates an
OFDM signal from the transmission packet input from packet
multiplexing section 221, and transmits the generated OFDM signal
by radio to base station apparatus 100 by RACH through antenna
element 223.
FIGS. 4A to 4D and FIGS. 5A to 5E show specific aspect of assigning
a transmission packet to the arbitrary subcarriers at arbitrary
time slots of RACH by the random access method according to this
embodiment. In this embodiment, RACH subchannel assigning section
211 is taken to process five subcarriers (SC) and five time slots
(TS) as a unit of RACH and assigns transmission packets randomly
within this one unit.
FIG. 4A shows an assignment of transmission packets to RACH in
radio communication terminal apparatus 200-1, and FIG. 4B to FIG.
4D show radio communication terminal apparatuses 200-2 to 200-4,
respectively. FIG. 4A and FIG. 4D show an aspect of randomly
assigning transmission packets to one of time slots and to one of
subcarriers of RACH, and FIG. 4B to one of subcarriers by all time
slots of RACH, and FIG. 4C to one of time slots in SC3 of RACH.
FIGS. 5A to 5E show transmission conditions of radio communication
terminal apparatuses 200-1 to 200-4 about SC1 to SC5 in timings of
TS1 to TS5, in the case that radio communication terminal
apparatuses 200-1 to 200-4 transmit transmission packets by the
assignment aspects shown in FIGS. 4A to 4D. FIG. 5A shows a
transmission condition in TS1, FIG. 5B in TS2, FIG. 5C in TS3, FIG.
5D in TS4 and FIG. 5E in TS5, respectively. FIGS. 5A to 5E append
"x" to all colliding transmission packets and "o " to transmission
packets first received at base station apparatus 100, per radio
communication terminal apparatuses 200-1 to 200-4.
As shown in FIGS. 5A to 5E, individual channels can be established
to base station apparatus 100, at a timing of TS1 in radio
communication terminal apparatus 200-1, at a timing of TS3 in radio
communication terminal apparatus 200-2, at a timing of TS5 in radio
communication terminal apparatus 200-3 and at a timing of TS4 in
radio communication terminal apparatus 200-4, respectively.
In this way, according to this embodiment, radio communication
terminal apparatus 200 assigns a plurality of duplicated
transmission packets to RACH randomly in RACH subchannel assigning
sections 211-1 to 211-c, and transmits the transmission packets at
the assigned time slots and subcarriers without waiting for a
response from base station apparatus 100 to the first transmission
packets, thereby establishing an individual channel to base station
apparatus 100 in a short time.
Furthermore, a plurality of transmission packets are assigned to
time slots of RACH randomly only according to radio communication
terminal apparatus 200-2 of this embodiment, and to subcarrier of
RACH only according to radio communication terminal apparatus 200-3
so that it is possible to reduce load of signal processing in RACH
subchannel assigning section 211 necessary for the assignment of
transmission packets compared to the case that the plurality of
transmission packets are assigned to time slots and subcarriers of
RACH randomly.
Moreover, according to radio communication terminal apparatus 200-1
or 200-4 of this embodiment, RACH subchannel assigning section 211
assigns a plurality of transmission packets to one of time slots of
RACH and also to one of subcarriers of RACH randomly so that, even
when many radio communication terminal apparatuses 200 belong to
the same cell, it is possible to reduce the likelihood of collision
of transmission packets in RACH.
In addition, the following applications and changes may be possible
to the random access method and radio communication terminal
apparatus 200 according to this embodiment.
In this embodiment, a case has been described where a plurality of
radio communication terminal apparatuses 200 assign transmission
packets randomly to time slots and subcarriers of RACH, but the
present invention is not limited to this, and, for example, it is
equally possible for a plurality of radio communication terminal
apparatuses 200 to transmit not OFDM signal, but packet signals of
a single carrier by radio communication, and assign those packet
signals randomly to the arbitrary time slots of RACH.
Furthermore, in this embodiment, a case has been described where
radio communication terminal apparatus 200 assigns randomly and
transmits transmission packets to time slots and subcarriers of
RACH, but the present invention is not limited to this, and, for
example, it is possible for radio communication terminal apparatus
200 to select spreading codes randomly instead of time slots and
subcarriers of RACH, and also perform code division of the
transmission packets using the selected spreading codes.
Furthermore, it is possible for radio communication terminal
apparatus 200 to assign transmission packets randomly to RACH
subchannel where time slots, subcarriers and spreading codes are
setting elements. As a result, even when many radio communication
terminal apparatuses 200 belong to the same cell, it is possible to
further reduce the likelihood of collision of transmission packets
in RACH.
Embodiment 2
FIG. 6 is a block diagram showing a configuration of radio
communication terminal apparatus 600 according to Embodiment 2 of
the present invention. Radio communication terminal apparatus 600
further includes priority determining section 601 and
number-of-duplications determining section 602 in radio
communication terminal apparatus 200 explained in Embodiment 1.
Therefore, radio communication terminal apparatus 600 includes many
components to show the same function as in the components of radio
communication terminal apparatus 200, so that such components are
assigned the same reference numerals as in the components of radio
communication terminal apparatus 200, and explanations thereof will
be omitted.
Priority determining section 601 determines a priority according to
kinds of services planned by radio communication terminal apparatus
600 after communication with base station apparatus 100 is started.
For example, in call services and video streaming services, since
allowable delay time is short (QoS delay requirement is demanding),
priority determining section 601 determines that high priority is
necessary in radio communication terminal apparatus 600 scheduled
to plan such service. Priority determining section 601 then inputs
information of the determined priority to number-of-duplications
determining section 602.
Number-of-duplications determining section 602 compares priority
information input from priority determining section 601 with a
conversion table provided in advance, determines the number of
duplications corresponding to the priority and inputs information
of the determined number of duplications to duplication section
202.
Next, the operations of radio communication terminal apparatus 600
will be explained using FIG. 7. FIG. 7 is a flow chart explaining
steps of the random access method according to Embodiment 2 of the
present invention.
First, in step ST710, priority determining section 601 determines a
priority of radio communication terminal apparatus 600 based on QoS
delay requirement information input from control section or the
like (not shown).
Subsequently, in step ST720, number-of-duplications determining
section 602 determines the number of duplications of transmission
packets according to the priority determined in step ST710, and
inputs information of the number of duplications to duplication
section 202.
Then, steps ST310 to 340 in Embodiment 1 are to be sequentially
executed.
Here, an example of the conversion table held in
number-of-duplications determining section 602 will be shown below
in "Table 1." This conversion table is made such that .alpha.=1,
based on c=.alpha..times.p . . . (1) {c is the number of
duplications, .alpha. is constant and p is the priority}.
TABLE-US-00001 TABLE 1 Priority Number of duplications 5 5 4 4 3 3
2 2 1 1
FIGS. 4A to 4D and FIGS. 5A to SE show specific aspect of assigning
a transmission packet to the arbitrary subcarriers at arbitrary
time slots of RACH by the random access method according to this
embodiment. In this embodiment, RACH subchannel assigning section
211 is taken to process five subcarriers (SC) and five time slots
(TS) as a unit of RACH and assigns transmission packets randomly
within this one unit. As can be seen in FIG. 4A, for example,
transmission packets (RACH access signals) are continuously
transmitted using five consecutive time slots TS1, TS2, TS3,
TS4,TS5 and are consecutive in the time domain.
Embodiment 3
FIG. 8 is a block diagram showing a configuration of radio
communication terminal apparatus 800 according to Embodiment 3 of
the present invention. Radio communication terminal apparatus 800
further includes number-of-duplications determining section 802 in
radio communication terminal apparatus 200 explained in Embodiment
1. Radio communication terminal apparatus 800 includes many
components to show the same function as in the components of radio
communication terminal apparatus 200 so that such components are
assigned the same reference numerals as in the components of radio
communication terminal apparatus 200, and explanations thereof will
be omitted.
Number-of-duplications determining section 802 compares information
of the number of retransmissions input from control section or the
like (not shown) with a conversion table provided in advance,
determines the number of duplications corresponding to the number
of retransmissions and inputs information of the determined number
of duplications to duplication section 202. In addition, "the
number of retransmissions" in this embodiment is incremented every
time all TS1 to TS5 shown in either of FIGS. 4A to 4D are
transmitted.
Next, the operations of radio communication terminal apparatus 800
will be explained using FIG. 9. FIG. 9 is a flow chart explaining
steps of a random access method according to this embodiment.
First, in step ST910, number-of-duplications determining section
802 compares the number of retransmissions input with the
conversion table provided in advance, determines the number of
duplications of the transmission packet and inputs information of
the determined number of duplications to duplication section
202.
Then, steps ST310 to ST340 in Embodiment 1 are to be sequentially
executed.
Here, an example of a conversion table held in
number-of-duplications determining section 802 will be shown below
in "Table 2." This conversion table is made such that .beta.=1,
based on c=F.times..beta. . . . (1) {c is the number of
duplications, F is the number of retransmissions and .beta. is
constant}.
TABLE-US-00002 TABLE 2 Number of retransmissions Number of
duplications 5 6 4 5 3 4 2 3 1 2
In this way, according to the random access method of this
embodiment, the number of transmission packets transmitted from
radio communication terminal 800 to base station apparatus 100 by
RACH increases according to the number of retransmissions so that,
out of a plurality of radio communication terminal apparatuses 800
belonging to the same cell, one with higher urgency is more likely
to establish the individual channel to base station apparatus 100
in a short time. As a result, according to the random access method
of this embodiment, the problems of deterioration of communication
quality, non-accessible state for communication and the like are
made less likely to occur in the plurality of the whole radio
communication terminal apparatuses 800 belonging to the same
cell.
Embodiment 4
FIG. 10 is a block diagram showing a configuration of radio
communication terminal apparatus 1000 according to Embodiment 4 of
the present invention. Radio communication terminal apparatus 1000
further includes radio reception section 1001, control information
extracting section 1002 and number-of-duplications determining
section 1003 in radio communication terminal apparatus 200
explained in Embodiment 1. Radio communication terminal apparatus
1000 includes many components to show the same function as in the
components of radio communication terminal apparatus 200 so that
such components are assigned the same reference numerals as in the
components of radio communication terminal apparatus 200, and
explanations thereof will be omitted.
Radio reception apparatus 1001 includes bandpass filter, A/D
converter, low noise amplifier, guard interval removal apparatus,
S/P converter, FFT apparatus, P/S converter or the like, and
acquires an OFDM signal to notify the number of radio communication
terminal apparatus 1000 which belong to cell A transmitted
regularly from base station terminal 100 through antenna element
223, and after predetermined reception signal proceeding to the
OFDM signal is performed, radio reception section 1001 inputs the
OFDM signal to control information extracting section 1002.
Control information extracting section 1002 extracts information of
the number of radio communication terminal apparatuses 1000
belonging to cell A out of the reception signal input from radio
reception section 1001, and inputs the extracted control
information to number-of-duplications determining section 1003.
Number-of-duplications determining section 1003 compares control
information input from control information extracting section 1002
with the conversion table provided in advance, determines the
number of duplications corresponding to the control information and
inputs the information of the determined number of duplications to
duplication section 202.
Next, the operations of radio communication terminal apparatus 1000
will be explained using FIG. 11. FIG. 11 is a flowchart explaining
steps for a random access method according to this embodiment.
First, in step ST1110, control information extracting section 1002
extracts control information from reception signal input from radio
reception section 1001.
Then, in step ST1120, number-of-duplication determining section
1003 learns the number of radio communication terminal apparatuses
1000 belonging to cell A based on control information and
determines the number of duplications corresponding to this number
with reference to the conversion table provided in advance.
Steps ST310 to ST340 in Embodiment 1 are to be sequentially
executed.
Here, an example of the conversion table held in
number-of-duplications determining section 1003 will be shown below
in "Table 3." In table 3, RACH subchannel assigning section 211 is
taken to process a total of 1000 RACH subchannels composed of 10
time slots and 100 subcarriers per time slot as a RACH unit, assign
100 transmission packets at maximum in one unit and furthermore,
radio communication terminal apparatus 1000 belongs to priorities 1
to 5.
TABLE-US-00003 TABLE 3 Number of duplications (number of terminals)
Priority (20) (35) (100) 5 7 (4) 5 (7) 1 (20) 4 6 (4) 4 (7) 1 (20)
3 5 (4) 3 (7) 1 (20) 2 4 (4) 2 (7) 1 (20) 1 1 (4) 1 (7) 1 (20) Sum
of the number of duplications 92 98 100
Furthermore, in FIG. 12A, correlation between the number of radio
communication terminal apparatuses 1000 belonging to cell A and the
number of duplications about priority 5 in this embodiment is
shown. Also, in FIG. 12B, correlation between the number of radio
communication terminal apparatuses 1000 belonging to cell A and the
number of duplications about priority 3 in this embodiment is
shown. As shown in FIG. 12A and FIG. 12B, this embodiment is set
such that the number of duplications of transmission packet in
duplication section 202 decreases with increase of the number of
radio communication terminal apparatuses 1000 belonging to the same
cell.
Therefore, according to the random access method of this
embodiment, as the number of radio communication terminal
apparatuses 1000 belonging to the same cell increases, the number
of transmission packets transmitted by radio communication terminal
apparatuses 1000 decreases so that it is possible to reduce the
likelihood of collision of transmission packets at RACH in the same
cell. As a result, according to the random access method according
to this embodiment, the problems of deterioration of communication
quality, non-accessible state for communication and the like are
made less likely to occur in the plurality of the whole radio
communication terminal apparatuses 1000 belonging to the same
cell.
In addition, although in the above embodiments, a case has been
described where the duplicated transmission packets are multiplexed
and transmitted in subcarriers or time slots, when, for example,
other resources such as radio communication terminal apparatus 200
include a plurality of transmission antennas, it is possible to
multiplex and transmit the duplicated transmission packets in
spatial resources such as transmission antenna and directivity
pattern, and spreading codes in CDMA system.
In addition, function blocks used in the explanations of the above
embodiments are typically implemented as LSI constituted by an
integrated circuit. These may be individual chips or partially or
totally contained on a single cup.
"LSI" is adopted here but this may also be referred to as "IC,"
"system LSI," "super LSI," or "ultra LSI" depending on differing
extents of integration.
Further, the method of circuit integration is not limited to LSI's,
and implementation using dedicated circuitry or general purpose
processors is also possible. After LSI manufacture, utilization of
an FPGA (Field Programmable Gate Array) or a reconfigurable
processor where connections and settings of circuit cells within an
LSI can be reconfigured is also possible.
Further, if integrated circuit technology comes out to replace
LSI's as a result of the advancement of semiconductor technology or
a derivative other technology, it is naturally also possible to
carry out function block integration using this technology.
Application in biotechnology is also possible.
The present application is based on Japanese Patent Application No.
2004-065625 filed on Mar. 9, 2004, the entire content of which is
expressively incorporated by reference herein.
INDUSTRIAL APPLICABILITY
The random access method and radio communication terminal apparatus
according to the present invention provides an advantage of
establishing an individual channel to the base station in a short
time, and is effective for using in the radio communication system
and the like with service demanding QoS delay requirement
planned.
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